How did a unmarried species of rodent invade South America in addition to and therefore speedily branch off into 350 novel species? The respond is uncomplicated -- the rodents were able to deed speedily across the continent unencumbered past times geographic boundaries that can't survive easily crossed such every bit an ocean.
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| Researchers examined how rodents of the Sigmodontinae identify unit of measurement branched out into 400 species across South America [Credit: Peter Meserve/Mammal Images Library of the American Society of Mammalogists] |
"Biologists bring long been fascinated past times the procedure of adaptive radiations, which occurs when a lineage undergoes rapid speciation that is correlated alongside variation inwards habitats that species evolve into, resulting inwards numerous species that differ inwards the environments inwards which they live," Schenk said. "Our written report was the outset to involve mensurate how movement across the landscape facilitated the speciation process."
Scientists inwards the past times had believed that when species evolved inwards a brusk menstruation of fourth dimension they diverged because of dissimilar ecological niches, non necessarily because of the mightiness to cross geographic boundaries.
Schenk in addition to Steppan flora that the species Sigmodontinae moved into South America in addition to speedily diversified across all the regions inside the continent. In near 8 1000000 years, they diversified into near 400 novel species that covered South America.
"That's actually fast," Steppan said.
As fourth dimension passed, the movement betwixt regions in addition to diversification slowed because the regions in addition to their associated ecological niches were essentially full.
"This [geography] largely tracks alongside what speciation is doing," Steppan said. "After that initial burst, it slows down."
Steppan studies evolutionary biological scientific discipline in addition to has e'er been interested inwards how species diversify. Most studies of species diversification involve islands where dissimilar groups of terrestrial species are walled off from competing interests past times body of body of water H2O allowing for animals to diversify based exactly on the ecology of the island.
But fiddling is known near how species diversify across the continuous geography of a continent.
Steppan said that he in addition to Schenk are looking at several possibilities for follow-up studies that focus on deoxyribonucleic acid locomote in addition to criterion other aspects of the rodents, such every bit the construction of their limbs in addition to skulls, to run into how these structures adapted to novel environments over time.
The query is published inwards the mag American Naturalist.
Author: Kathleen Haughney | Source: Florida State University [October 03, 2018]
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